Bitwise operation utilities in rust. Uses PrimInt from the num_traits crate.

utils.rs

/// Update a value in a specific bitmask, though return the unwritten value first
pub fn toggle_bit<T: PrimInt>(bitmask: &mut T, index: usize, value: bool) -> bool {
    let copy = ((*bitmask >> index) & T::one()) == T::one();

    if value {
        *bitmask = *bitmask | (T::one() << index);
    } else {
        *bitmask = *bitmask & (!(T::one() << index));
    }

    copy
}

/// Enable all the bits between "start" and "end" in the binary representation of a T
/// Start is inclusive, end is exclusive
pub fn enable_in_range<T: PrimInt>(start: usize, end: usize) -> T {
    assert!(end >= start);
    let bits = size_of::<T>() * 8;

    if end == bits {
        !((T::one() << (start)) - T::one())
    } else if start == bits {
        T::zero()
    } else {
        ((T::one() << (start)) - T::one()) ^ ((T::one() << end) - T::one())
    }
}

/// Check if a bit at a specific index is set
pub fn is_bit_enabled<T: PrimInt>(bitset: T, index: usize) -> bool {
    (bitset >> index & T::one()) == T::one()
}